1. Field of the Invention
The present invention relates to a technique of detecting related objects from an input image including a plurality of object images and performing image processing in accordance with the detection result.
2. Description of the Related Art
In recent years, digital cameras and photography scanners have become very popular, and it has become easy to convert a photographic image into digital data. In particular, it has become popular to deal with a photographic image in the form of digital data on a personal computer. Photographic images in the form of digital data can be edited, copied and pasted in a desired fashion on a personal computer using various kinds of application software.
However, photographic images often have factors which can cause degradation in image quality such as a color blur, for reasons described below. For example, in the case of a digital camera, a CCD used in the digital camera can detect infrared wavelength components which are not perceptible by human eyes. Although a filter may be used to remove infrared components, the above problem cannot be completely solved. Furthermore, due to a limitation in the performance of a CPU disposed in a camera and due to real-time constraints, a satisfactory result is not always obtained in a color balance correction performed by a camera. It is known that human beings can make corrections in terms of differences in color of light sources (that is, human being can adapt to differences in color of light sources). In contrast, cameras faithfully capture differences in color of light sources. Therefore, a color blur can occur even if a camera correctly detects colors. Similar problems can also occur in photography scanners and flatbed scanners, and a satisfactory color balance is not always obtained in digital data converted from a negative or reversal film even if the negative or reversal film is ideal.
To avoid the above problems, a technique has been proposed to generate a histogram from pixel data of an original image and detect pixel data corresponding to a predetermined frequency of occurrence, whereby an image correction is performed on the basis of the detected pixel data.
In some relatively high-level applications in which memory is used in a highly efficient manner and the processing speed is optimized, an image with a large size is internally divided into plural parts and processed by a plurality of image drawing commands. In this case, information of divided image parts is analyzed to detect a plurality of drawing commands associated with the same original image, and the same color processing condition is set to the drawing commands found to be associated with the same original image. A specific example of such a technique is disclosed in U.S. patent application Ser. No. 09/336,987, filed Jun. 21, 1999, which application is assigned to the assignee of the present invention.
In this technique, detection of divided image parts originating from the same original image is performed on the basis of overlapping among image parts and also on the basis of the image information. In some applications, when an image is rotated and the resultant image is output, the image is divided into a large number of parts. In such a case, management information including coordinates associated with each drawing command can become very large. If the management information becomes too large, it becomes impossible to store information associated with all coordinates.